tipping at full-serve gas stations
Okay, so I have a few of full-serve gas stations near me (where they pump the gas for you because your ass is too lazy to get out in the rain and pump it your damn self). I use these places as often as I can because I fit that lazy bit.
Now, the ones I usually go to are priced the same $/gal. as self-serve gas stations, though there are other full-serve places nearby that charge more because they are full-serve. Also, nothing fancy goes on like window washing or things like that. Simply pump and pay.
My question is, are we supposed to tip the gas pumper at these places, and if so how much? I never have tipped, yet some people say you should. I'd like to know the general consensus on this answer.